A filter arrangement of the above-mentioned type is known from DE19519352A1, in which a hollow cylindrical filter insert is arranged in a cylindrical filter housing. The liquid to be filtered, for example fuel for an internal combustion engine, is guided in the radially outer chamber of the filter assembly, so that it can penetrate the filter insert from the outside into the inner cavity. The outlet for the filtered liquid is connected to the inner cavity.
At the beginning of a liquid feed into the outer chamber of the filter arrangement, a certain amount of air upstream from the liquid is transported into the outer chamber. This amount of air is likewise pressed by the subsequent pressure of the liquid through the filter insert and thus also reaches the outlet of the filter arrangement. This is very disadvantageous, in particular in use as a fuel or oil filter, because the downstream units, such as the internal combustion engine, can be hindered during operation by air pockets in the fuel supply.
A venting arrangement is therefore provided in DE19519352A1, which consists of a simple bore in a cap which is sealingly applied on the filter element, wherein the bore is connected with an outlet channel for the escaping air. This venting arrangement permits the escape of air contained in the filter arrangement, but also allows the inflow of air when no fuel is pumped into the internal combustion engine. Especially in internal combustion engines with start/stop systems, the internal combustion engine is often shut down and thus does not pump fuel, with the result that air may enter the fuel management system in the stop phase.
The object of the invention is to design a filter element such that the ingress of air into the fuel management system is prevented in a stationary internal combustion engine.
A further object of the invention is to provide a filter system for receiving such a replaceable filter element, which can prevent the entry of air into the fuel management system in a stationary internal combustion engine.
The aforementioned objects are achieved according to one aspect of the invention in that, in a filter element for a filter system, in particular for a fuel filter, with a first fluid path for filtering a first fluid, in particular for filtering fuel, and a second fluid path with a fluid line for carrying a second fluid, in particular for ventilating the filter system, a non-return valve is arranged in the second fluid path, which non-return valve closes if a flow of the first fluid through the filter element is interrupted. The filter element is replaceably arranged in the housing of the filter system and has a filter media body through which the first fluid path leads.
Advantageous embodiments and advantages of the invention result from the additional claims, the description and the drawings.